/*
 * Copyright (c) 2004-2022, University of Oslo
 * All rights reserved.
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 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors 
 * may be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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 */
package org.hisp.dhis.commons.filter;

import java.util.Collection;

/**
 * Utility class for collection filtering.
 *
 * @author Lars Helge Overland
 */
public class FilterUtils {
  /**
   * Filters the given collection using the given {@link Filter}.
   *
   * @param <T> type.
   * @param collection the {@link Collection}.
   * @param filter the filter.
   * @param <V> the type of the collection members.
   * @return the filtered collection, null if any input parameter is null.
   */
  public static <T extends Collection<V>, V> T filter(T collection, Filter<V> filter) {
    if (collection == null || filter == null) {
      return null;
    }

    collection.removeIf(v -> !filter.retain(v));

    return collection;
  }

  /**
   * Filters the given collection using the given {@link Filter} retaining only items which do not
   * pass the filter evaluation.
   *
   * @param <T> type.
   * @param collection the {@link Collection}.
   * @param filter the filter.
   * @param <V> the type of the collection members.
   * @return the inverse filtered collection, null if any input parameter is null.
   */
  public static <T extends Collection<V>, V> T inverseFilter(T collection, Filter<V> filter) {
    if (collection == null || filter == null) {
      return null;
    }

    collection.removeIf(filter::retain);

    return collection;
  }
}
